<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://unpkg.com/vue"></script>
</head>
<body>
<ol id="app">
    <!--创建一个todo-item组建的实例-->
    <todo-item></todo-item>
</ol>
<script>
    /*注册一个组件*/
    Vue.component('todo-item',{
            template:'<li>这是个待办项</li>'
        }
    )
//    创建根实例
     var app=new Vue({
         el:'#app'
     })
</script>
</body>
</html>